Sauna exterior



FIG. 1 is a top left side exterior perspective view of the sauna of the present invention;

FIG. 2 is a front exterior elevation view thereof; and,

FIG. 3 is a left exterior elevation view thereof.

The broken lines shown in the drawings are directed to environment, are for informational purposes only, and form no part of the claimed design. 

The ornamental design for a sauna exterior, as shown and described. 